U.S. patent application number 15/508419 was filed with the patent office on 2017-10-19 for oil mist separation method and oil separator.
This patent application is currently assigned to TOKYO ROKI CO., LTD.. The applicant listed for this patent is TOKYO ROKI CO., LTD.. Invention is credited to Kosaku ISHIDA, Yoshitaka WATANABE, Tsuyoshi YAO.
Application Number | 20170296955 15/508419 |
Document ID | / |
Family ID | 55439302 |
Filed Date | 2017-10-19 |
United States Patent
Application |
20170296955 |
Kind Code |
A1 |
ISHIDA; Kosaku ; et
al. |
October 19, 2017 |
OIL MIST SEPARATION METHOD AND OIL SEPARATOR
Abstract
A rotor separates oil mist from a target gas. This rotor
includes a separation disk group having separation disks including
a plurality of truncated cone shape plate members layered. The
separation disk group includes a first space (hollow part with
attachment opening) and a second space (gaps between separation
disks), the first space formed on a rotation center side of the
rotor and the second space formed between separation disks that are
laid over and in communication with the first space. The first
space contains an oil introducing portion (gap between the upper
end of the spindle and the upper side sealing member). Target gas
is introduced into the first space, target gas and oil introduced
from the oil introducing portion are made to flow from the first
space to the second space to be discharged outward from an outer
peripheral edge of the separation disk group, while rotating the
rotor.
Inventors: |
ISHIDA; Kosaku;
(Yokohama-shi, JP) ; YAO; Tsuyoshi; (Yokohama-shi,
JP) ; WATANABE; Yoshitaka; (Yokohama-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOKYO ROKI CO., LTD. |
Yokohama-shi, Kanagawa |
|
JP |
|
|
Assignee: |
TOKYO ROKI CO., LTD.
Yokohama-shi, Kanagawa
JP
|
Family ID: |
55439302 |
Appl. No.: |
15/508419 |
Filed: |
September 5, 2014 |
PCT Filed: |
September 5, 2014 |
PCT NO: |
PCT/JP2014/073515 |
371 Date: |
March 2, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B04B 5/12 20130101; B01D
47/02 20130101; B01D 47/00 20130101; B04B 5/005 20130101; B04B 1/08
20130101; B04B 7/14 20130101; B01D 45/14 20130101; B01F 3/04
20130101 |
International
Class: |
B01D 45/14 20060101
B01D045/14; B01D 47/02 20060101 B01D047/02; B04B 1/08 20060101
B04B001/08; B04B 7/14 20060101 B04B007/14 |
Claims
1. An oil mist separation method that separates oil mist from
target gas by using an oil separator including a rotor that is
rotatable together with a spindle and by rotating the rotor, the
method comprising: including in the rotor a separation disk group,
the separation disk group having separation disks made with a
plurality of truncated cone shape plate members layered in an axis
direction of the spindle; including in the separation disk group a
first space and a second space, the first space being formed on a
rotation center side of the rotor and the second space being formed
between the separation disks that are laid over and being in
communication with the first space; disposing in the first space an
oil introducing portion that introduces oil; introducing the oil
from the oil introducing portion together with the target gas into
the first space, while the rotor is in a rotating state; and
allowing the target gas to flow from the first space into the
second space together with the oil introduced from the oil
introducing portion and to be discharged outward from an outer
peripheral edge of the separation disk group.
2. The oil mist separation method according to claim 1, wherein the
oil separator includes a nozzle that is provided to protrude from a
circumferential face of the spindle on a lower side with respect to
the separation disks and that rotates the spindle by injecting oil,
and a spindle shaft that rotatably supports the spindle and that
has internally formed an oil supply passage to supply the oil, the
oil introducing portion is configured with a gap between the
spindle and the spindle shaft, and a part of the oil supplied to
the oil supply passage is injected from the nozzles and another
part of the oil is introduced from the oil introducing portion into
the first space.
3. The oil mist separation method according to claim 2, wherein the
target gas is blow-by gas that is supplied from the engine and oil
supplied to the oil supply passage is a lubricant of the
engine.
4. The oil mist separation method according to claim 2, wherein the
oil separator includes a third space in which oil injected from the
nozzles flows down and in which the target gas is introduced, and a
partitioning member that is disposed at a boundary between the
third space and the first space, the target gas is made to contact
the oil injected from the nozzles and the oil mist is primarily
separated from the target gas in the third space, the target gas
that had the oil mist primarily separated is introduced into the
first space by the partitioning member, the target gas is made to
flow from the first space into the second space together with the
oil introduced from the oil introducing portion, and the target gas
is made to contact the oil introduced from the oil introducing
portion and the oil mist is secondarily separated from the target
gas in the second space.
5. An oil separator including a rotor that is rotatable together
with a spindle and being configured to separate oil mist from
target gas by rotating the rotor, comprising: a separation disk
group that is included in the rotor and that has separation disks
made with a plurality of truncated cone shape plate members layered
in an axis direction of the spindle; a first space and a second
space that are included in the separation disk group, the first
space being formed on a rotation center side of the rotor and
having the target gas flow in, and the second space being formed
between the separation disks that are laid over and being in
communication with the first space; and an oil introducing portion
that is disposed in the first space, the oil introducing portion
being configured to introduce oil.
6. The oil mist separation method according to claim 3, wherein the
oil separator includes a third space in which oil injected from the
nozzles flows down and in which the target gas is introduced, and a
partitioning member that is disposed at a boundary between the
third space and the first space, the target gas is made to contact
the oil injected from the nozzles and the oil mist is primarily
separated from the target gas in the third space, the target gas
that had the oil mist primarily separated is introduced into the
first space by the partitioning member, the target gas is made to
flow from the first space into the second space together with the
oil introduced from the oil introducing portion, and the target gas
is made to contact the oil introduced from the oil introducing
portion and the oil mist is secondarily separated from the target
gas in the second space.
Description
TECHNICAL FIELD
[0001] The present invention relates to a separation method for
separating oil mist contained in target gas from the gas and to an
oil separator.
BACKGROUND ART
[0002] There has been known an oil separator that separates oil
mist contained in target gas from the gas. For example, an oil
separator described in Patent Literature 1 uses a rotor provided
between a gas inlet port and a gas discharge port to separate oil
mist from the gas using centrifugal force. This rotor is structured
with a plurality of separation disks placed one over the other.
These separation disks are configured with truncated cone shape
plate members that have the outer peripheral side parts curved
obliquely upward such that the radius on the upper side becomes
large. The inner circumferential side parts of the separation disks
have formed thereto openings that penetrate the separation disks in
the thickness direction. In this way, a space is formed to the
inner circumferential side part of this rotor.
[0003] This oil separator introduces crankcase gas (blow-by gas)
being the target gas into the space on the inner circumferential
side of the rotor. The crankcase gas introduced into this space
flows to the outer peripheral side of the rotor through the gaps
created between the separation disks rotating at high speed and
condenses the oil mist within these gaps to separate the oil mist
from the crankcase gas.
CITATION LIST
Patent Literature
[0004] Patent Literature 1 Japanese translation of PCT
International Application No. 2003-513792
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0005] In the above-described oil separator, the oil mist contained
in the crankcase gas is taken into the boundary layers that are
formed to the surfaces of the separation disks accompanied, by the
high-speed rotation of the separation disks. Then the oil mist
taken into the boundary layers merges and condenses on the surface
of the separation disks with the other oil mist similarly taken in.
The diameter of the of the separation disks need to be widened to
take in much oil mist in order to increase the oil mist separation
efficiency since there is an extremely small amount of oil mist
contained in the crankcase gas. Thus there arises an issue that the
size of the oil separator would grow along with the increase in the
diameter of the separation disks.
[0006] The present invention has been made under these
circumstances, and an object of the present invention is to
increase the separation efficiency during separation of oil mist
contained in target gas from the gas.
SUMMARY OF INVENTION
[0007] To achieve the above-described object, the present invention
is an oil mist separation method that separates oil mist from
target gas by using an oil separator including a rotor that is
rotatable together with a spindle and by rotating the rotor, the
method characterized to include in the rotor a separation disk
group, the separation disk group having separation disks made with
a plurality of truncated cone shape plate members layered in an
axis direction of the spindle, include in the separation disk group
a first space and a second space, the first space being formed on a
rotation center side of the rotor and the second space being formed
between the separation disks that are laid over and being in
communication with the first space, dispose in the first space an
oil introducing portion that introduces oil, introduce the oil from
the oil introducing portion together with the target gas into the
first space, while the rotor is in a rotating state, and allow the
target gas to flow from the first space into the second space
together with the oil introduced from the oil introducing portion
and to be discharged outward from an outer peripheral edge of the
separation disk group.
[0008] According to the oil mist separation method of the present
invention, both the target gas introduced into the first space and
the oil introduced into the first space are made to flow into the
second space formed between the separation disks. Here, the oil is
recognized to spread in a film-like manner on the surface of the
separation disks since the rotor is rotated at high-speed. And the
oil mist contained in the target gas is taken into the boundary
layer formed to the surface of the oil film. The oil film has a
higher compatibility compared to the separation disk since the oil
of the oil film is the same as that of the oil mist. Therefore, the
boundary layer formed to the surface of the oil film can take in
the oil mist in a more efficient manner compared to the boundary
layers formed to the surface of the separation disks.
[0009] In the above-described oil mist separation method, it is
preferable that the oil separator includes a nozzle that is
provided to protrude from a circumferential face of the spindle on
a lower side with respect to the separation disks and that rotates
the spindle by injecting oil, and a spindle shaft that rotatably
supports the spindle and that has internally formed an oil supply
passage to supply the oil, the oil introducing portion is
configured with a gap between the spindle and the spindle shaft,
and a part of the oil supplied to the oil supply passage is
injected from the nozzles and another part of the oil is introduced
from the oil introducing portion into the first space. According to
this separation method, the oil supplied to the oil supply passage
can be used as the power for rotating the spindle as well as used
for forming oil films.
[0010] In the above-described oil mist separation method, it is
preferable that the target gas is blow-by gas that is supplied from
the engine and oil supplied to the oil supply passage is a
lubricant of the engine. In this separation method, the oil mist
originates from engine lubricant and since the oil film is the
engine lubricant, oil mist can be further efficiently taken in by
the increased compatibility characteristics.
[0011] In the above-described oil mist separation method it is
preferable that, the oil separator includes a third space in which
oil injected from the nozzles flows down and in which the target
gas is introduced, and a partitioning member that is disposed at a
boundary between the third space and the first space, the target
gas is made to contact the oil injected from the nozzles and the
oil mist is primarily separated from the target gas, in the third
space, the target gas that had the oil mist primarily separated is
introduced into the first space by the partitioning member, the
target gas is made to flow from the first space into the second
space together with the oil introduced from the oil introducing
portion, and the target gas is made to contact the oil introduced
from the oil introducing portion and the oil mist is secondarily
separated from the target gas, in the second space. With this
separation method, the oil mist contained in target gas is
primarily separated using the oil injected from the nozzles and
then secondarily separated using the oil introduced from the oil
introducing portion so that the oil mist can be separated at a
further increased level.
[0012] Further, the present invention is an oil separator including
a rotor that is rotatable together with a spindle and being
configured to separate oil mist from target gas by rotating the
rotor, the oil separator characterized to include a separation disk
group that is included in the rotor and that has separation disks
made with a plurality of truncated cone shape plate members layered
in an axis direction of the spindle, a first space and a second
space that are included in the separation disk group, the first
space being formed on a rotation center side of the rotor and
having the target gas flow in, and the second space being formed
between the separation disks that are laid over and being in
communication with the first space, and an oil introducing portion
that is disposed in the first space, the oil introducing portion
being configured to introduce oil.
Advantageous Effects of Invention
[0013] According to the present invention, the separation
efficiency during separation of oil mist contained in target gas
from the gas can be increased.
BRIEF DESCRIPTION OF DRAWINGS
[0014] FIG. 1 is a schematic diagram illustrating a closed
crankcase ventilation system.
[0015] FIG. 2 is a front view of an oil separator.
[0016] FIG. 3 is a plan view of the oil separator.
[0017] FIG. 4 is a vertical section view of the entire oil
separator viewed from the right side.
[0018] FIG. 5 is a vertical section view of a lower side part of
the oil separator viewed from the right side.
[0019] FIG. 6 is a vertical section view of a rotor part of the oil
separator viewed from the front side.
[0020] FIG. 7 is a horizontal section view of the middle part of
the oil separator cut along line VII-VII in FIG. 4.
[0021] FIG. 8 is a vertical section view illustrating in an
enlarged manner parts proximate the PCV valve.
[0022] FIG. 9 is a partially enlarged cross-sectional view
illustrating an inner circumferential side space formed on the
inner circumferential side of the rotor and separation spaces
formed between the separation disks.
[0023] FIG. 10 is a diagram illustrating oil film formed to the
separation disk surface and flows of blow-by gas.
[0024] FIG. 11 is a diagram schematically illustrating how the oil
mist is taken in.
DETAILED DESCRIPTION
[0025] The following describes embodiments of the present invention
with reference to the drawings. The following gives a description
with an example of a closed crankcase ventilation system 1
(hereinafter referred to as a ventilation system 1).
[0026] As illustrated in FIG. 1, the ventilation system 1 includes
an oil separator 2 and a breather pipe 3. The oil separator 2
processes blow-by gas (corresponding crankcase gas, that is, target
gas containing oil mist) discharged from an engine 4 to separate
the oil mist. This embodiment includes the oil separator 2 mounted
at a side surface of the engine 4. The breather pipe 3 defines a
return flow passage, through which the processed blow-by gas
discharged from the oil separator 2 returns to an intake-side flow
passage of the engine 4.
[0027] In this ventilation system 1, the blow-by gas is guided out
from the engine 4 through a gas guide pipe 5 and introduced into
the oil separator 2. Then the oil mist contained in the blow-by gas
is taken into the oil supplied from the engine 4 at the interior of
the oil separator 2 and returned to the engine 4 together with this
oil. Meanwhile, the processed blow-by gas having oil mist removed
is discharged from the oil separator 2 and then returned to the
intake-side flow passage 6 through the breather pipe 3.
Specifically, the processed blow-by gas is returned to a part at
which an air filter 7 is coupled to a turbocharger 8 in the
intake-side flow passage 6. The returned blow-by gas is mixed with
fresh air sent from the air filter 7 and is compressed by the
turbocharger 8. Afterwards, the blow-by gas is cooled by a charge
cooler 9 and is supplied to the engine 4.
[0028] The following describes the oil separator 2. As illustrated
in FIGS. 2 and 3, this oil separator 2 includes a housing 11, which
includes a lower case 12 and an upper case 13. The housing 11
houses such as a rotor unit, a sectioning member, and a PCV valve
(all to be described later in detail) in an internal space
thereof.
[0029] As illustrated in FIG. 2, the lower case 12 is a part that
sections a lower side part in the housing 11. The lower case 12 is
constituted of a box-shaped member having a bottom and an opened
top surface. An upper end portion of the lower case 12 has a
circular fitting portion 14 disposed thereon and a lower end
portion 15 of the upper case 13 fits thereto. Hereby, the lower
case 12 and the upper case 13 are hermetically coupled. As
illustrated in FIG. 4, the lower case 12 includes on the back
surface thereof a communication tube portion 16 facing backward.
This communication tube portion 16 is a tubular member that serves
as the discharge port of the oil used in the oil separator 2.
Hereby, the internal space of the communication tube portion 16 is
communicated to the internal space of the engine 4. As illustrated
in FIGS. 2 and 3, the communication tube portion 16 includes a
flange 17 at its distal end portion where this flange 17 joined to
the side surface of the engine 4. Further, a suction pipe 18 is
provided to the upper portion on the left of the lower case 12 in a
manner protruding toward to the left side.
[0030] The gas guide pipe 5 is coupled to this suction pipe 18. The
blow-by gas from the engine 4 is introduced from the gas guide pipe
5 through the suction pipe 18 and into the interior of the oil
separator 2 by the suction pressure of the engine 4 and the
pressure on the crankcase side. During such, the suction pressure
of the engine 4 and the pressure on the crankcase side is
appropriately adjusted. And the suction pipe 18 functions as a gas
introducing portion.
[0031] As illustrated in FIGS. 2 and 4, a joint 20 of the oil guide
pipe 19 is provided on the bottom surface of the lower case 12.
This joint 20 is coupled to one end of an oil supply pipe 21, which
is illustrated in FIG. 1. The oil supply pipe 21 is provided for
supplying the oil sent out from the engine 4 to the oil guide pipe
19. The oil that has been supplied to the oil guide pipe 19 is
injected from the nozzles of the rotor unit, which will be
described later in detail, and then used as the power to rotate the
rotor unit. In the following description, the oil injected from the
nozzles is also called power oil for the sake of convenience. This
power oil is a part of the lubricant used at the engine 4 and thus
maintained at a temperature between 80 and 110.degree. C.
[0032] As illustrated in FIG. 2, the upper case 13 is a member
mounted to the lower case 12 from above. This upper case 13
includes a cylindrical body cover 22 including a roof part and a
disk-shaped top surface cover 23. The body cover 22 is mounted in
an airtight manner to the lower case 12. The top surface cover 23
is mounted in an airtight manner to the upper end portion of the
body cover 22. Further, as also illustrated in FIG. 3, a
cylindrical gas discharge portion 24 is provided to protrude upward
at a center of the top surface cover 23. This gas discharge portion
24 is a part from which the processed blow-by gas is discharged.
The aforementioned breather pipe 3 is coupled to this gas discharge
portion 24 via an L-shaped outlet pipe 25.
[0033] The following describes an internal structure of the oil
separator 2 with reference to FIG. 4. Here in FIG. 4, the left side
corresponds to the front side of the oil separator 2 and the right
side corresponds to the back side of the oil separator 2. As shown
in FIG. 4, a PCV valve 26, a rotor unit 27 and a partitioning
member 28 are disposed in the housing 11. The PCV valve 26 is
disposed to the top part of the housing 11. Specifically, the PCV
valve 26 is mounted between the main body cover 22 and the top face
cover 23 while being covered by the top face cover 23. The rotor
unit 27 is disposed at a vertically middle portion of the housing
11. Specifically, the rotor unit 27 is rotatably disposed in the
internal space partitioned by the main body cover 22. The
partitioning member 28 is disposed directly below the rotor 31 that
constitutes the rotor unit 27. This partitioning member 28 is
positioned with the brim portion 44 sandwiched between the lower
end portion 15 of the upper case 13 and the fitting portion 14 of
the lower case 12.
[0034] The following describes the internal structure of the lower
case 12 with reference to FIG. 5. In also FIG. 5, the left side
corresponds to the front side of the oil separator 2 and the right
side corresponds to the back side of the oil separator 2. As shown
in FIG. 5, the communication tube portion 16 is integrally provided
on the rear portion of the lower case 12 such that the internal
space of the lower case 12 and the internal space of the
communication tube portion 16 are in communication. The bottom face
of the lower case 12 is inclined downward toward the communication
tube portion 16. A cylindrical oil guide pipe 19 is disposed upward
from the bottom face of the lower case 12. The joint portion 20 is
provided to the lower end of the oil guide pipe 19 and the upper
end of the oil guide pipe 19 is fixed with a fixing frame 29. The
fixing frame 29 is a frame body mounted to the inner
circumferential side of the fitting portion 14 and includes a frame
portion shaped to come along the inner circumferential face of the
fitting portion 14 and a crossed portion that is in a "+" shape,
which is provided to the inner side of the frame portion. The upper
end of the oil guide pipe 19 is inserted into the through hole 29a
made to the crossing of the crossed portion.
[0035] Although not illustrated in FIG. 5, the suction pipe 18 is
provided, at a height that comes directly under the fitting portion
14, on the left side face of the lower case 12. The internal space
of the lower case 12 and the internal space of the suction pipe 18
are made to communicate with each other. Hereby, the blow-by gas is
suctioned from the engine 4 into the internal space of the lower
case 12. Further, the power oil injected from the nozzles 38 is
injected to the inner wall face of the tapered portion 45 of the
partitioning member 28. This power oil flows down along the inner
wall face of the tapered portion 45 and the inner wall face of the
lower case 12. Here, the power oil flowing down contacts the
blow-by gas suctioned into the internal space of the lower case 12.
A part of the oil mist contained in the blow-by gas is taken into
the power oil by the power oil coming into contact with the blow-by
gas. As a result, the amount of oil mist contained in the blow-by
gas is reduced.
[0036] In this way, the internal space of the lower case 12
corresponds to the primary separation chamber (third space SP3)
that primarily separates oil mist from the blow-by gas by having
the power oil injected from the nozzles 38 flow downward and
simultaneously having blow-by gas introduced therein from the
engine 4 such that the blow-by gas and the power oil come into
contact.
[0037] Further, since the temperature of the power oil injected
from the nozzles 38 becomes high at 80 to 110.degree. C., the power
oil heats the oil separator 2 from the lower case 12 side. Hereby,
performance failures of the oil separator 2 caused by such as
freezing can be suppressed even when the oil separator 2 is used in
cold regions.
[0038] Next, with reference to FIGS. 6 and 7, the following gives
descriptions of the rotor unit 27. This rotor unit 27 is a
mechanism to separate the oil mist contained in the blow-by gas and
the rotor unit 27 includes a rotor 31, a spindle 32, and a spindle
shaft 33.
[0039] The rotor 31 is a part that separates the oil mist from the
blow-by gas as illustrated in FIG. 6. The rotor 31 includes a
plurality of separation disks 34, an upper holder 35, and a lower
holder 36. The separation disks 34 are circular or polygonal plate
members in plan view that have the outer peripheral side parts
inclined downward toward the outer peripheral side. In other words,
the separation disks 34 are plate materials fabricated in a
truncated cone shape or a truncated pyramid shape.
[0040] Each separation disk 34 of this embodiment has a diameter of
80 to 120 mm and a thickness of 0.3 to 0.4 mm, and is manufactured
in a circular shape in plan view by molding resin. These separation
disks 34 are layered in the axial direction of the spindle 32 to
constitute a separation disk group. For the convenience of
explanation, the separation disks 34 are illustrated with intervals
provided between each other; however, the actual intervals are
defined to be extremely narrow, for example, at 1 mm or less.
[0041] The central side parts of the separation disks 34, which
correspond to the upper base parts of the truncated cones
respectively is provided with an attachment opening 34a. As
illustrated in FIG. 7, the attachment opening 34a in the present
embodiment is an octagonal hollow portion in plan view in which the
disk retaining portion 35a provided to the upper holder 35 is
inserted. When the disk retaining portion 35a is inserted in the
plurality of separation disks 34, a hollow part (first space SP1)
is formed to the rotor 31 with this attachment opening 34a.
Further, 16 ribs 34b for securing gaps (second spaces SP2) between
the layered separation disks 34 are radially formed to the surfaces
on the outer peripheral side parts of the separation disks 34 in an
equiangular manner. These ribs 34 allow the gaps between the
separation disks 34 to be certainly secured and hereby these gaps
and the hollow part of the rotor 31 communicate with each
other.
[0042] As illustrated in FIG. 6, the upper holder 35 is a member
that holds the plurality of layered separation disks 34 from above.
Similarly, the lower holder 36 is a member that holds the
separation disks 34 from below. A disk retaining portion 35a is
provided at the rotation center of the upper holder 35 in a
downward facing manner. This disk retaining portion 35a is
configured with eight plate members 35b which are radially formed
to extend from the rotation center of the rotor 31. The side edges
of the respective plate members 35b come into contact with the
respective tips of the attachment openings 34a provided to the
separation disks 34. In the outer peripheral edge of the lower
holder 36, a plurality of coupling arms 37 for coupling to the
upper holder 35 are disposed. In this embodiment, the four coupling
arms 37 are provided circumferentially at intervals of 90 degrees.
The upper ends of the coupling arms 37 are joined to the upper
holder 35, and thereby the plurality of separation disks 34, the
upper holder 35, and the lower holder 36 are integrated.
[0043] This rotor 31 has a cylindrical appearance. On the inner
circumferential side that is the rotation center of the rotor 31,
there is a hollow part, and the hollow part vertically extends
through. The spindle 32 is inserted into this hollow part and the
spindle 32 and the rotor 31 are joined to one another. The spindle
32 and the rotor 31 according to the present embodiment are coupled
by the eight plate members 35b that constitute the disk retaining
portion 35a being joined to the circumferential face of the spindle
32. The disk retaining portion 35a is inserted into the respective
attachment openings 34a of the separation disks 34. Thus, the rotor
31 rotates, together with the spindle 32, about the axis of the
spindle 32.
[0044] The nozzles 38 project from the peripheral surface parts of
the spindle 32, the parts being located below with respect to the
rotor 31. Each of the nozzles 38 is a part from which the oil
supplied through the spindle shaft 33 is injected to generate a
driving power to rotate the spindle 32 and the rotor 31. The
nozzles 38 of this embodiment include cylindrical nozzle bodies 38a
and injection holes 38b disposed at distal end portions of the
nozzle bodies 38a. Base ends of the nozzles 38 are coupled to the
spindle 32, and the distal ends of the nozzle bodies 38a are
closed. The nozzle bodies 38a are mounted at an angle of 45 degrees
obliquely downward with respect to the axial direction of the
spindle 32. The three nozzle bodies 38a are circumferentially
disposed at intervals of 120 degrees. The injection hole 38b is
disposed on a side surface at the distal end portion of the nozzle
body 38a. More specifically, the injection hole 38b is disposed in
a direction perpendicular to the axial direction of the nozzle body
38a, the direction being a direction in which oil is injected
horizontally.
[0045] The spindle shaft 33 is a pillar member serving as a bearing
of the spindle 32, and supports the spindle 32 in a rotatable
manner. The spindle shaft 33 internally includes a first oil supply
passage 39 to supply the oil. A lower end portion of the spindle
shaft 33 is joined to an upper end of the oil guide pipe 19. As
described above, the oil supply pipe 21 is coupled to the joint 20
of the oil guide pipe 19. Accordingly, the oil supplied through the
oil supply pipe 21 passes through the oil guide pipe 19, and then
flows into the first oil supply passage 39 as power oil.
[0046] A gap that has its top and bottom closed is formed between
the spindle 32 and the spindle shaft 33. This gap serves as a
second oil supply passage 40. The second oil supply passage 40 is
in communication with the first oil supply passage 39 and the
nozzles 38, and is filled with oil supplied from the first oil
supply passage 39. A part of the oil supplied to the second oil
supply passage 40 flows into the nozzle bodies 38a and thereafter
injected from the injection holes 38b.
[0047] The lower end of the second oil supply passage 40 is sealed
with a cylindrical lower side sealing member 41. Similarly, the
upper end of the second oil supply passage 40 is sealed with a
cylindrical upper side sealing member 42. A small amount of oil
leaks out from the gaps created between the lower side sealing
member 41 and the spindle, and the upper side sealing member 42 and
the spindle 32 along with rising of the oil pressure. When the
rotor 31 of this embodiment is rotated at a speed that creates a
centrifugal force of substantially 200 G, oil of about 50 to 200
mL/min is introduced through the gap created between the upper end
of the spindle 32 and the upper side sealing member 42 and into the
inner circumferential side space (first space SP1) of the rotor 31.
For the purpose of convenience, the oil introduced from the upper
end of the second oil supply passage 40 and into the inner
circumferential space of the rotor 31 is also called cleansing oil
in the following description.
[0048] The cleansing oil that has been introduced into the inner
circumferential space of the rotor 31 flows down this space and
along the outer surface of the spindle 32 and spreads along the
surfaces of the plate members 35b of the disk retaining portion 35a
toward the outer peripheral side. The cleansing oil that had spread
to the outer peripheral side flows from the edges of the attachment
openings 34a and into the gaps (second space SP2) formed between
the separation disks 34. Then the cleansing oil that had flown into
the gaps spreads along the surface to the outer peripheral side of
the separation disks 34 to be discharged outward from the outer
peripheral edges of the separation disks 34.
[0049] In this way, the upper end of the second oil supply passage
40, specifically the gap between the upper end of the spindle 32
and the upper side sealing member 42 serves as the oil introducing
portion that introduces a part of the oil supplied to the second
oil supply passage 40 as the cleansing oil. This cleansing oil is
also at a high temperature between 80 to 110.degree. C. so that the
oil heats the rotor 31 and its proximate areas from the inside.
Hereby, performance failures of the oil separator 2 caused by such
as freezing can be suppressed even when the oil separator is used
in cold climate areas.
[0050] The following describes the partitioning member 28. The
partitioning member 28 is disposed between the rotor 31 and the
nozzles 38. The partitioning member 28 is a member that partitions
the internal space of the housing 11 into an internal space of the
lower case 12 (primary separation chamber, third space SP3) and an
internal space of the upper case 13 and at the same time forms the
flow passage that guides the blow-by gas of the lower case 12 to
the hollow part (first space SP1) of the rotor 31.
[0051] This partitioning member 28 has an outer peripheral portion
43, a brim portion 44 and a tapered portion 45. The outer
peripheral portion 43 is a cylindrical part and is formed to
surround the rotor 31. This outer peripheral portion 43 has an
elongated slot 43a formed inclined with respect to the vertical
direction. Cleansing oil that is discharged outward from the outer
peripheral edges of the separation disks 34 hits against the inner
wall face of the outer peripheral portion 43. The cleansing oil
that had hit the inner wall face spreads along this inner wall face
and flows downward while circulating. During such, a part of the
oil is discharged through the slots 43a to the outer peripheral
side space. This makes it difficult for oil to accumulate in the
gap created between the outer peripheral portion 43 and the rotor
31 and thus can suppress problems of oil being taken away by the
flow of the blow-by gas. As a result, the performance of oil mist
separation from the blow-by gas can be improved.
[0052] The brim portion 44 that is located in the middle in the
height direction of the outer peripheral portion 43 projects to the
side. As mentioned above, this brim portion 44 is a part that
positions the partitioning member 28 and is sandwiched between the
lower end portion 15 of the upper case 13 and the fitting portion
14 of the lower case 12. The tapered portion 45 is disposed on the
inner circumferential side with respect to the outer peripheral
portion 43, and has a tapered shape in which the diameter is
gradually reduced from the lower end of the outer peripheral
portion 43 toward the top. An upper end opening 45a of the tapered
portion 45 is disposed proximate from below the surface center of
the lower end of the rotor 31.
[0053] The lower end portion of the spindle 32, the lower end
portion of the spindle shaft 33, the nozzles 38 and the fixing
frame 29 are disposed on the inner circumferential side of the
tapered portion 45 and below the upper end opening 45a. As
mentioned above, the power oil that has been injected from the
nozzles 38 hits against the inner wall face of the tapered portion
45 to flow down along this inner wall face and thereafter flows
down into the internal space of the lower case 12. When the power
oil flows down, the power oil comes into contact with the blow-by
gas and the oil mist contained in the blow-by gas is primarily
separated. The blow-by gas having the oil mist primarily separated,
rises up the inner circumferential side of the tapered portion 45
to be guided to the hollow portion (first space SP1) of the
rotor.
[0054] The following describes the PCV valve 26. As illustrated in
FIG. 8, the PCV valve 26 includes a diaphragm 46, upper springs 47,
and lower springs 48.
[0055] The diaphragm 46 is a disc-shaped valve element and is
manufactured by molding rubber and resin. The upper springs 47 and
the lower springs 48 are elastic members to support the diaphragm
46 in a manner such that the diaphragm 46 can move vertically. That
is, the upper springs 47 are disposed above the diaphragm 46 and
the lower springs 48 are disposed below the diaphragm 46. The
diaphragm 46 is movably supported by being sandwiched between these
upper springs 47 and lower springs 48.
[0056] The diaphragm 46 vertically moves according to the
intake-side pressure of the engine 4 and the internal pressure of
the crankcase, to adjust the flow of the blow-by gas. That is,
under an excessively large intake pressure (negative pressure) of
the engine 4, the diaphragm 46 moves toward the blow-by gas
discharge side (upward), and under a high pressure of the side
close to the crankcase, the diaphragm 46 moves toward the opposite
side (downward). Hereby, the flow rate of the blow-by gas is
appropriately adjusted. Further, the engine 4 (crank case) pressure
is also appropriately adjusted.
[0057] Next, the separation of the oil mist with the oil separator
2 of this embodiment will be described. This oil separator 2 is
characterized to separate the oil mist in particularly the rotor
31. Therefore, description will be given mainly on the separation
of the oil mist in the rotor 31.
[0058] This oil separator 2 rotates the rotor 31 using the oil (a
part of lubricant) supplied from the engine 4 for power. In other
words, the oil supplied through the oil supply pipe 21 after
flowing through the oil guide pipe 19 flows into the first oil
supply passage 39 of the spindle shaft 33. Thereafter, a part of
the oil after flowing through the second oil supply passage 40 is
injected out from the nozzles 38 as the power oil, as indicated
with the arrow with the reference sign F1 in FIG. 9. Further,
another part of the oil supplied from the engine 4 after flowing
through the second oil supply passage 40 as cleansing oil is
introduced from the upper end (oil introducing portion) of the
second supply passage 40 into the space on the inner
circumferential side in the rotor 31, as indicated with the arrows
with the reference sign F2.
[0059] In this way, the oil separator 2 injects oil, which had been
supplied from the engine 4, from the nozzles 38 and introduces oil
into the hollow part of the rotor 31 from the upper end of the
second oil supply passage 40. As mentioned above, the temperature
of the oil rises to 80 to 110.degree. C. by the operation of the
engine 4 to also raise the temperature of the oil separator 2 so
that the moisture in the rotor 31 can be kept from freezing.
[0060] The blow-by gas from the engine 4 is introduced into the
internal space of the lower case 12 with the suction of air by the
engine 4. Meanwhile, the power oil injected from the nozzles 38 are
sprayed against the inner wall face of the partitioning member 28
and thereafter flows down along the inner wall face of the
partitioning member 28 and the inner wall face of the lower case
12, as mentioned above, as indicated with the arrow with the
reference sign F3. Hereby, the blow-by gas contacts the power oil
and a part of the oil mist contained in the blow-by gas is taken
into the power oil. In other words, a primary separation of the oil
mist takes place.
[0061] The blow-by gas having the oil mist primarily separated,
rises up the inner circumferential space of the tapered portion 45
with the suction of air by the engine 4 and thereafter guided to
the center portion along in the plane direction at the lower end of
the rotor 31 as indicated with the arrow with the reference sign
F11. Then the blow-by gas is made to flow into the hollow part
(first space SP1) of the rotor 31. Since the rotor 31 rotates at
high speed in this hollow part, the cleansing oil introduced
therein spreads along the surface of the plate members 35b that
constitute the disk retaining portion 35a and flows from the edge
portions of the attachment openings 34a and into the gaps (second
spaces SP2) between the separation disks 34, as indicated with the
arrows with the reference signs F4. The blow-by gas is also made to
flow from the edge portions of the attachment openings 34a and into
the gaps (second spaces SP2) between the separation disks 34, as
indicated with the arrows with the reference signs F12.
[0062] As illustrated in FIG. 10, the cleansing oil that had flown
into the gaps between the separation disks 34 spreads evenly along
the surfaces of the separation disks 34 since the rotor 31 rotates
at high speed. As indicated with the arrow with the reference sign
F13, the blow-by gas flows while contacting the oil films OFs
formed on the surfaces of the separation disks 34. And as shown
enlarged in FIG. 11, a boundary layer BL is formed on the surface
of the oil film OF. Then, when the blow-by gas flows along the
surface side of the boundary layer BL toward the outer peripheral
edge of the separation disk 34, as indicated with the arrow with
the reference sign F13, the oil mist contained in the blow-by gas
is taken into the boundary layer BL as indicated with the arrow
with the reference sign F5. The oil mist taken into the boundary
layer BL is made to move by the centrifugal force indicated with
the reference sign CF and merges with the oil film OF.
[0063] Here, since the oil mist originates from the lubricant
similar to the oil film OF (cleansing oil), the oil mist has a
higher compatibility characteristic (wettability) with the oil film
OF compared to the separation disks 34. Hereby, the boundary layers
BL formed on the surface of the oil films OF can more effectively
take in the oil mist with respect to the boundary layers BL formed
on the surfaces of the separation disks 34. As a result, high
separation efficiency can be achieved even when the separation
disks 34 are configured with small diameters and therefore allowing
to downsize the oil separator 2.
[0064] Further, this oil separator 2 can separate oil mist as well
as vaporize the water contained in the lubricant. In other words,
since the temperature of the cleansing oil is high between 80 to
110.degree. C., the oil films OFs formed on the surfaces of the
separation disks 34 also has the temperature of the oil films OFs
in a range that is sufficient to vaporize the moisture.
Furthermore, since the oil films OFs are densely formed due to the
multiply layered separation disks 34, the temperature of the oil
films OFs can be maintained. Even furthermore, the oil films OFs
being formed on the entire surfaces of the separation disks 34,
secures a sufficient area for efficiently vaporizing moisture. For
these reasons, water contained in the lubricant can be efficiently
vaporized. Hereby, problems of emulsion being formulated to the
lubricant can be suppressed.
[0065] The cleansing oil that had taken in the oil mist, as
indicated with the arrow with the reference sign F6 in FIG. 10, is
discharged outward from the outer peripheral edges of the
separation disks 34. The discharged cleansing oil hits against the
outer peripheral portion 43 of the partitioning member 28 and flows
down while circulating along the inner wall face of this outer
peripheral portion 43. Hereby, an oil film is also formed to the
inner wall face of the outer peripheral portion 43. The oil mist
contained in the blow-by gas is captured and the captured oil mist
is kept from being re-dispersed as well by the discharged cleansing
oil being taken into the oil film.
[0066] When the cleansing oil reaches the lower end of the outer
peripheral portion 43, the oil flows through the drain hole (not
shown) formed to the bottom portion of the partitioning member 28
to be discharged to the internal space (third space SP3) of the
lower case 12. As mentioned above, since power oil flows into the
internal space of the lower case 12, the cleansing oil mixes with
the power oil. Then the power oil and the cleansing oil merges with
the oil mist taken in and flow through the communication tube
portion 16 to be returned to the engine 4.
[0067] Meanwhile, the processed blow-by gas having oil mist
separated being discharged outside from the outer peripheral edges
of the separation disks 34, rises up the interior of the housing 11
by the suction of the engine 4, as indicated with the arrow with
reference sign F14. Here, the moisture vaporized from the oil film
OF does not condensate and moves together with the blow-by gas
since the inner portion of the oil separator is heated with the
cleansing oil and the power oil. Then the processed blow-by gas
passes through the PCV valve 26, the gas discharge portion 24 and
the gas discharge portion 25 together with the moisture vaporized
from the oil film OF to be discharged from the oil separator 2.
Thereafter, the processed blow-by gas is returned to the
intake-side flow passage 6 through the breather pipe 3.
[0068] According to the oil separator 2 of the present embodiment,
oil films OFs are formed on the surfaces of the separation disks 34
with the cleansing oil in this way so that oil mist can be
effectively separated from the blow-by gas.
[0069] Additionally, the oil supplied to the first oil supply
passage 39 and the second oil supply passage 40 is used as the
power for rotating the spindle 32 as well as used to form the oil
films OFs thereby simplifying the device configurations.
[0070] Further, since the oil mist originates from the lubricant of
the engine 4 and the oil films OFs are the lubricant of the engine
4, compatibility thereof are increased to allow the oil mist to be
taken into the oil films OFs in a further efficient manner.
[0071] Further after primarily separating the oil mist by allowing
the blow-by gas to contact the power oil in the internal space of
the lower case 12, the processed blow-by gas is made to contact the
cleansing oil at the interior (gaps between the separation disks
34) of the rotor 31 for secondary separation of the oil mist and
hereby the oil mist can be separated at a high level.
[0072] The description of the above-described embodiment is for
ease of understanding of the present invention and does not limit
the present invention. The present invention may be modified or
improved without departing from the gist and includes the
equivalents. For example, the present invention may be configured
as follows.
[0073] The hollow part of the rotor 31 in the present embodiment is
formed with octagonal attachment openings 34a, in plan view,
however, there is no limitation to such configuration as long as it
is a space in which blow-by gas can be introduced.
[0074] The separation disks 34 are not limited to a truncated cone
shape and may be a truncated pyramid shape. Note that, when the
separation disks 34 are in a truncated pyramid shape, it is
preferable that it is at least a quadrangular pyramid shape and
more preferably at least an octagonal pyramid shape.
[0075] The lower case 12, the communication tube portion 16, the
suction pipe 18 and the oil guide pipe 19 of the present embodiment
are manufactured of cast metal, however, they may be manufactured
by molding resin.
[0076] The cleansing oil supply passage in the aforementioned
embodiment was partly used in common with the power oil, however,
there is no limitation to such configuration. The cleansing oil may
be supplied through a passage of a system separate from the power
oil. In such case, the rotation of the rotor 31 may be performed by
a motor. In other words, the spindle 32 should be rotated with the
motor.
[0077] The target gas is not limited to blow-by gas. The present
invention can be applied as long as the device separates oil mist
from target gas containing oil mist.
[0078] When introducing target gas in the aforementioned
embodiment, oil mist introduced the target gas primarily separated
at the lower case 12 into the hollow part of the rotor 31, however,
there is no limitation to such configuration. The target gas may be
directly introduced into the hollow part of the rotor 31.
[0079] An outer peripheral portion 43 of the partitioning member 28
was exemplified to have elongated slots 43a provided thereto,
however, the elongated slots 43a are to be provided according to
need.
REFERENCE SIGNS LIST
[0080] 1 closed crankcase ventilation system, [0081] 2 oil
separator [0082] 3 breather pipe, [0083] 4 engine, [0084] 5 gas
guide pipe [0085] 6 intake-side flow passage, [0086] 7 air filter,
[0087] 8 turbocharger [0088] 9 charge cooler, [0089] 11 housing,
[0090] 12 lower case, [0091] 13 upper case [0092] 14 fitting
portion in lower case [0093] 15 lower end portion in upper case
[0094] 16 communication tube portion, [0095] 17 flange, [0096] 18
suction pipe [0097] 19 oil guide pipe, [0098] 20 joint of oil guide
pipe [0099] 21 oil supply pipe, [0100] 22 body cover [0101] 23 top
surface cover, [0102] 24 gas discharge portion [0103] 25 outlet
pipe, [0104] 26 PCV valve, [0105] 27 rotor unit [0106] 28
partitioning member, [0107] 29 fixing frame, [0108] 29a penetration
holes of fixing frame, [0109] 31 rotor [0110] 32 spindle, [0111] 33
spindle shaft, [0112] 34 separation disk [0113] 34a attachment
opening of separation disk [0114] 34b rib of separation disk,
[0115] 35 upper holder [0116] 35a disk retaining portion [0117] 35b
plate member of disk retaining portion [0118] 36 lower holder,
[0119] 37 coupling arm [0120] 38 nozzle, [0121] 38a nozzle body,
[0122] 38b injection hole [0123] 39 first oil supply passage [0124]
40 second oil supply passage [0125] 41 lower sealing member, [0126]
42 upper sealing member [0127] 43 outer peripheral portion of
partitioning member [0128] 43a slit, [0129] 44 brim portion of
partition member [0130] 45 tapered portion of partition member
[0131] 45a upper end opening of tapered portion [0132] 46 collar
portion of partition member [0133] 47 upper spring of PCV valve
[0134] 48 lower spring of PCV valve [0135] SP1-SP3 first to third
spaces, [0136] OF oil film, [0137] BL boundary layer, [0138] F1 to
F6 flows of oil [0139] F11 to F14 flows of blow-by gas
* * * * *